In recent years, membrane separation technology has become the focus of industrial waste acid treatment and recovery with many advantages. As a kind of environmentally friendly membrane separation technology, diffusion dialysis is widely used in the field of waste acid. The experiment was carried out with 0.55 mol/L hydrochloric acid as raw material. Besides, the effects of operating parameters such as the flow rate of feed acid (620 mL/min) and flow ratio of water and acid (0.61.4) were examined. The transport of hydrochloric acids through anion-exchange membrane DF-120 in a counter-current continuous dialyzer was investigated in detail. The important parameter, permeability coefficient of the membrane, was optimized by polynomial fitting. A simpler mathematical model of lumped parameters established, which could predict the hydrochloric acid recovery rate during the diffusion dialysis process. These obtained points were investigated to verify the mathematical model and it was proved excellent. The model was used for predictions under more detailed experimental operating conditions. It also provided reference methods and arguments for actual industrial production.